Water based bond sewing thread and method of manufacturing the same

ABSTRACT

A method of manufacturing a bonded sewing thread comprises the steps of forming coating liquid by adding catalyst of 1 to 5 wt % to a mixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt %, aliphatic isophthalic diisocyanate of 7 to 11 wt % (MW is 222.2 and viscosity is 500 to 1000 CPS/25° C.), polyester sulfur oxide diol of 1 to 5 wt % as water based monomer (MW is 400 to 500 and viscosity is 500 to 1000 CPS/25° C.), and water of 49 to 53 wt % are uniformly mixed; coating the sewing thread by dipping the sewing thread in the mixed coating liquid; a dry step of drying the coated sewing thread in a temperature range of 120 to 180° C. for 20 to 60 seconds; curing the dried sewing thread in a temperature range of 150 to 200° C. for 20 to 40 seconds; elongating the cured sewing thread in a temperature range of 150 to 200° C. for 15 to 20 seconds so that the sewing thread has elongation of 30 to 60%; and winding the elongated sewing thread.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a water based bond sewing thread and amethod of manufacturing the same. More particularly, the presentinvention relates to a water based bond sewing thread and a method ofmanufacturing the same, in which a risk of fading and a change of coloris remarkably decreased and color reproducibility and a feeling of useare excellent even for a long time use, working environments can beimproved and a risk of a fire is low because a water based coatingmethod not generating any toxic gases is used, additional process is notused in case where waterproof thread is manufactured by using waterbased bond sewing thread, and water treatment can be easily performedbecause some waterproof liquid can be mixed in a process of coating thesewing thread.

2. Background of the Invention

In general, sewing thread refers to a thread used in a sewing machine.The sewing thread is subjected to a dyeing process and produced after awinding process.

However, the common sewing thread is problematic in that the strength ofthe thread is weak, the thread gets loose or entangled at a high-speedsewing task, and textiles are damaged because of friction.

In order to solve the problems, a bonded sewing thread is provided byperforming a bonding process on sewing thread. There is also providedwaterproof sewing thread produced by performing additional waterproofprocessing on a bonded sewing thread in order to prevent water frominfiltrating into the sewing thread, according to circumstances.

A solvent based method is used in the existing bonding processingmethod. Raw materials for the bonding processing include albamide,ethylene glycol, and methyl alcohol which are agitated and used. The rawmaterials need to continuously heated and agitated.

Furthermore, in a process of coating the sewing thread, the materialsneed to be continuously heated in order to prevent the materials frombeing hardened. After the padding processing is performed as describedabove, dry, elongation, winding, and packaging processes are performed.

In case where waterproof sewing thread is fabricated as described above,after the dry and elongation processes are completed, a process ofapplying additional water repellents and another dry process need to beperformed.

Furthermore, the existing sewing thread is problematic in that feelingis hard because of a lack of flexibility, some toxic gases are generatedand a risk of a fire resulting from the volatilization of methyl alcoholexists when the bonding process is performed on the sewing thread,methanol needs to be frequently added and a dual heating device isneeded because a solvent is volatile, and an additional agitator needsto be installed.

In addition, a feeling of use and a feeling of coloring are decreasedbecause there is a great change in the color between before the threadis dyed and after the thread is processed. Accordingly, an additionaldevice is required because second water repellent processing has to beperformed after dry and elongation processes. In particular, there is aproblem in that the cost rises because the dependency of imported rawmaterials is high.

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made in view of the aboveproblems occurring in the prior art, and the present invention providesa bonded sewing thread in which flexibility is excellent, durability andstrength are high and freely controlled, a risk of fading and a changeof color is remarkably decreased and color reproducibility and a feelingof use are excellent even for a long time use, the manufacturing cost islow, and a supplied price is economical.

Furthermore, the present invention provides a bonded sewing thread inwhich working environments can be improved and a risk of a fire is lowbecause a water based coating method not generating any toxic gases isused, additional process is not used in case where waterproof thread ismanufactured by using water based bond sewing thread, and watertreatment can be easily performed because some waterproof liquid can bemixed in a process of coating the sewing thread.

According to an aspect of the present invention, there is provided amethod of manufacturing a bonded sewing thread, comprising a coatingliquid formation step of forming coating liquid by adding catalyst of 1to 5 wt % to a mixture of 95 to 99 wt % in which polyester polyol of 39to 43 wt %, aliphatic isophthalic diisocyanate of 7 to 11 wt %(molecular weight (MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C.(Brookfield viscometer)), polyester sulfur oxide diol of 1 to 5 wt % aswater based monomer (molecular weight (MW) is 400 to 500 and viscosityis 500 to 1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to53 wt % are uniformly mixed; a padding step of coating the sewing threadby dipping the sewing thread in the mixed coating liquid; a dry step ofdrying the coated sewing thread in a temperature range of 120 to 180° C.for 20 to 60 seconds; a curing step of curing the dried sewing thread ina temperature range of 150 to 200° C. for 20 to 40 seconds; anelongation step of elongating the cured sewing thread in a temperaturerange of 150 to 200° C. for 15 to 20 seconds so that the sewing threadhas elongation of 30 to 60%; and a winding step of winding the elongatedsewing thread.

According to another aspect of the present invention, there is provideda bonded sewing thread manufactured by coating the sewing thread bydipping the sewing thread in coating liquid, produced by mixing catalystof 1 to 5 wt % and a mixture of 95 to 99 wt % in which polyester polyolof 39 to 43 wt %, aliphatic isophthalic diisocyanate of 7 to 11 wt %(molecular weight (MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C.(Brookfield viscometer)), polyester sulfur oxide diol of 1 to 5 wt % aswater based monomer (molecular weight (MW) is 400 to 500 and viscosityis 500 to 1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to53 wt % are uniformly mixed; drying the coated sewing thread in atemperature range of 120 to 180° C. for 20 to 60 seconds; curing thedried sewing thread in a temperature range of 150 to 200° C. for 20 to40 seconds; elongating the cured sewing thread in a temperature range of150 to 200° C. for 15 to 20 seconds so that the sewing thread haselongation of 30 to 60%; and winding the elongated sewing thread.

In accordance with water based bond sewing thread and the method ofmanufacturing the same according to the present invention, there areadvantages in that flexibility is excellent, durability and strength arehigh and freely controlled, a risk of fading and a change of color isremarkably decreased and color reproducibility and a feeling of use areexcellent even for a long time use, the manufacturing cost is low, and asupplied price is economical.

Furthermore, there are advantages in that working environments can beimproved and a risk of a fire is low because a water based coatingmethod not generating any toxic gases is used, additional process is notused in case where waterproof thread is manufactured by using waterbased bond sewing thread, and water treatment can be easily performedbecause some waterproof liquid can be mixed in a process of coating thesewing thread.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a bonded sewing thread and a method of manufacturing thesame according to the present invention are described in detail.

In the method of manufacturing the bond sewing thread, a coating liquidformation process is performed to form coating liquid by adding catalystof 1 to 5 wt % to a mixture of 95 to 99 wt % in which polyester polyolof 39 to 43 wt %, from among polyester materials, aliphatic isophthalicdiisocyanate of 7 to 11 wt % (molecular weight (MW) is 222.2 andviscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), polyestersulfur oxide diol of 1 to 5 wt % as water based monomer (molecularweight (MW) is 400 to 500 and viscosity is 500 to 1000 CPS/25° C.(Brookfield viscometer)), and water of 49 to 53 wt % are uniformlymixed.

A padding process is performed to coat the sewing thread by dipping thesewing thread in the mixed coating liquid.

A dry process is performed to dry the coated sewing thread in atemperature range of 120 to 180° C. for 20 to 60 seconds.

A curing process is performed to cure the dried sewing thread in atemperature range of 150 to 200° C. for 20 to 40 seconds; an elongationprocess of elongating the cured sewing thread in a temperature range of150 to 200° C. for 15 to 20 seconds so that the sewing thread haselongation of 30 to 60 W.

A winding process is performed to wind the elongated sewing thread.

The above method is described below in more detail.

First, in the coating liquid formation process, the coating liquid isformed by adding catalyst of 1 to 5 wt % to a mixture of 95 to 99 wt %in which polyester polyol of 39 to 43 wt %, aliphatic isophthalicdiisocyanate of 7 to 11 wt % (molecular weight (MW) is 222.2 andviscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), polyestersulfur oxide diol of 1 to 5 wt % as water based monomer (molecularweight (MW) is 400 to 500 and viscosity is 500 to 1000 CPS/25° C.(Brookfield viscometer)), and water of 49 to 53 wt % are uniformlymixed.

A main material for the coating liquid is polyester. In order toincrease an adhesive property, aliphatic isophthalic diisocyanate (thatis, a non-yellow characteristic cross-linking agent) of 7 to 11 wt %(where, a molecular weight (MW) is 222.2 and viscosity is 500 to 1000CPS/25° C. (Brookfield viscometer)) is added.

In case where aliphatic isocyanate of less than 7 wt % is mixed, theadhesive strength of the coating liquid is low. In case where aliphaticisocyanate of more than 11 wt % is mixed, the viscosity of the coatingliquid is high and so workability is low. Accordingly, aliphaticisocyanate of 7 to 11 wt % preferably is mixed.

In order to make the coating liquid water-based, polyester sulfur oxidediol (that is, a water based monomer material) of 1 to 5 wt % having anMW of 400 to 500 and viscosity of 500 to 1000 CPS/25° C. (Brookfieldviscometer) (where, wt % is not a known art) is adeed. Further, water of49 to 53 wt % is added as a diluent for controlling viscosity.

The reason why water is added is that water serves as a diluent and thepadding process may not be properly performed because the main materialhas a high viscosity.

In case where water of less than 49 wt % is mixed, viscosity is high andso workability is difficult. In case where water of more than 53 wt % ismixed, there is a possiblity that the adhesive strength of the coatingliquid may be low. Accordingly, water of 49 to 53 wt % preferably isadded.

The catalyst of 1 to 5 wt % is added, preferably 2 wt %. The catalystfunctions to rapidly dry the coating liquid padded to the bond sewingthread and to control the strength of the bond sewing thread. The amountof the catalyst mixed can be various according to circumstances. In casewhere the catalyst of less than 1 wt % is mixed, the strength of thebond sewing thread is weak and the dry time is long. In case where thecatalyst of more than 5 wt % is mixed, the padding process for thecoating liquid is difficult because of the evaporation of moisture andthe efficiency of the sewing thread may be low because of high strength.Accordingly, the catalyst of 1 to 5 wt % preferably is mixed.

In accordance with a preferred embodiment of the present invention, thecatalyst is formed by mixing aliphatic isophthalic diisocyanate andethyl acetate in order to control strength. Catalyst components,composed of aliphatic isophthalic diisocyanate of 75%, ethyl acetate of15%, and other additives of 10%, can preferably be used.

In general, in the coating liquid formation process, a mixture isagitated because albamide (that is, a chip state) has to be heated whilethe albamide is dissolved using using a solvent. However, the coatingliquid according to the present invention is a water based material,which does not require an additional heating process. Accordingly, theprocess is convenient and the time taken to perform the process isreduced.

In the padding process, the sewing thread is coated by dipping thesewing thread in the mixed coating liquid. This process is performed tomake uniform the bonding of the sewing thread. A bonding pickup ratiomay be in the range of 80 to 100% depending on the thickness of a rawthread.

In the padding process, the coating is performed by dipping the coatingliquid in a padding vessel and soaking the sewing thread. Here, thecoating liquid does not become hard at normal temperature because it isa water based material. Accordingly, the process can be rapidlyperformed because an additional heating process is not required.

In the dry process, the coated sewing thread is dried in a temperaturerange of 120 to 180° C. for 20 to 60 seconds. In a process of the coatedsewing thread passing through a heat chamber, the coated sewing threadis fully dried.

In case where the dry temperature is less than 120° C. or the dry timeis less than 20 seconds, the dry of the coated sewing thread is notproperly performed. In this case, there is a possibility that thecoating liquid may be peeled off. In case where the dry temperature ismore than 180° C. or the dry time is less than 60 seconds, the coatingliquid and the sewing thread may be thermally transformed and energy canbe lost. Accordingly, it is preferred that the coated sewing thread bedried in a temperature range of 120 to 180° C. for 20 to 60 seconds.

In the curing process, the dried sewing thread is thermally processed ina temperature range of 150 to 200° C. for 20 to 40 seconds in order toincrease elongation and harden the sewing thread. In particular, thecuring process must be performed when the sewing thread is processed byusing water repellents. In this case, the sewing thread is thermallyprocessed in a sealed heat chamber in a temperature range of 150 to 200°C. for 20 to 40 seconds so that the dried coating liquid and the sewingthread can be integrally sticked.

In case where the processing temperature is less than 150° C. or theprocessing time is less than 20 seconds, the thermal processing purposefor increasing elongation and hardening the sewing thread cannot beachieved. In case where the processing temperature is more than 200° C.or the processing time is more than 40 seconds, the coating liquid andthe sewing thread may be thermally transformed, and energy can be lost.Accordingly, it is preferred that the thermal processing be performed ina temperature range of 150 to 200° C. for 20 to 40 seconds.

In the elongation process, the cured sewing thread is elongated in atemperature range of 150 to 200° C. for 15 to 20 seconds so that thesewing thread has elongation of 30 to 60%. The elongated sewing threadis subjected to the winding process, packed, and finally completed as aproduct.

The elongation process can be performed by using a common method. Inthis method, in order to achieve elongation of 30 to 60%, the sewingthread is elongated and processed in a temperature range of 150 to 200°C. for 15 to 20 seconds which are similar to those of the curing processperformed in order to increase elongation.

For reference, the elongation process is a process of reducing thelinear density by lengthily extending a bundle of threads in a spinningprocess. Through the process, the orientation of polymer within a fiberis improved, and tensile strength and elasticity of the fiber areincreased.

In accordance with a preferred embodiment of the present invention, thecoating liquid can further comprise water repellent liquid in whichwater repellents of 3 to 8 wt % are mixed with water based bond of 46 to51 wt % and water of 46 to 51 wt %.

If the water repellent liquid is added to the coating liquid, the waterrepellent liquid penetrates the sewing thread, thus preventing moistureor a change of the dimensions.

Accordingly, an anti-working ability (that is, an ability to resist thepenetration of water or moisture) can be increased.

The water based bond of 46 to 51 wt % is mixed. Adhesive strength mustbe given to the water based bond so that the water repellents firmlystick to the sewing thread. Water is used to control viscosity and thussolve the difficulty of a task. It is preferred that a ratio of thewater based bond versus water be 1:1. Fluorinated water repellents areused as the water repellents. It is preferred that the water repellentsof 3 to 8 wt % be mixed so that the water repellents are uniformly mixedwith the coating liquid and a desired water repellent function can beproperly performed.

Furthermore, the bond sewing thread of the present invention ismanufactured by coating the sewing thread by dipping the sewing threadin coating liquid, produced by mixing catalyst of 1 to 5 wt % and amixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt %(where, wt % is not a known art), from among known polyester materials,aliphatic isophthalic diisocyanate of 7 to 11 wt % (molecular weight(MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfieldviscometer)), polyester sulfur oxide diol of 1 to 5 wt % as water basedmonomer (molecular weight (MW) is 400 to 500 and viscosity is 500 to1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to 53 wt % areuniformly mixed; drying the coated sewing thread in a temperature rangeof 120 to 180° C. for 20 to 60 seconds; curing the dried sewing threadin a temperature range of 150 to 200° C. for 20 to 40 seconds;elongating the cured sewing thread in a temperature range of 150 to 200°C. for 15 to 20 seconds so that the sewing thread has elongation of 30to 60%; and winding the elongated sewing thread.

For reference, the sewing thread is strong, and it has a uniformthickness and a smooth and flat surface. The sewing thread isdifferently used according to the characteristics and thickness offabric. In general, two-ply thread is used for hand sewing thread, andthree-ply thread or six-ply thread are used for machine sewing thread.

Regarding the thickness of thread, {circle around (1)} the thickness ofthread is indicated by the thread count and denier, and there aretwo-ply thread and three-ply thread according to the number of twistedstrands. {circle around (2)} Cotton, wool, and spinning threads areindicated by the thread count ('s), and silk and synthetic fibers areindicated by denier (d). {circle around (3)} The thread count is a fixedweight system indicating thread fineness. When cotton thread of 1 poundin weight is 840 yd in length, it is called as the thread count 1 (1's),and a higher thread count is a finer thread. Denier is a fixed lengthsystem indicating thread fineness. When thread of 9,000 m in length is 1g in weight, it is called as 1 denier (1 d), and a higher denier is athicker thread. {circle around (4)} The number of twisted strands isindicated by writing the thickness of 1 strand, drawing ′/′, and thenwriting the number of twisted strands. In this case, for example, ‘75d/3’ indicates that 3 plies each being 75 d thread are put together andactually has the thickness of 225 d. Three-ply thread is chiefly usedfor sewing thread. If the number of strands is not indicated, it isconsidered as three plies.

Furthermore, regarding the types of threads, {circle around (1)} in thecase of cotton thread, twisted thread (that is, mercerized cotton) iscommonly strong and lustrous and used as sewing thread. Accordingly, thetwisted threads are classified into the yard counts 30(30′s/3 and60′s/2/3), 40(40′s/3 and 80′s/2/3), 50(50′s/3 and 30′s/2), 60(60′s/3 and40′s/2), 80(80′s/3 and 50′s/2), 100s(100′s/3), and so on. The yardcounts 30 to 50 are used for thick threads and cotton and hemp cloths,and the yard counts 60 to 80 are used for thin fabrics. {circle around(2)} Silk threads are suitable for needlework of wool, silk, and mixedspinning fabrics, 21 d/4×3 threads are chiefly used, which is 252 d inthickness with the dimension of 21×4×3. {circle around (3)} Polyester issuitable for needlework of synthetic fiber fabrics or synthetic fibersblended fabrics. 75 d/3 threads are chiefly used. {circle around (4)}Thick and lustrous threads of 100 d/3 or higher are used for buttonholes or top stitches. There are rayon thread, polyester thread, andsilk thread. {circle around (5)} T/C threads are mixed threads with 65%of polyester and 35% of cotton and suitable for needlework of syntheticfiber fabrics, cotton fabrics, and T/C blended fabrics. {circle around(6)} Hemp threads are chiefly used for sealing threads of shoemaking.

The coating liquid is produced by mixing catalyst of 1 to 5 wt % and amixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt %(where, wt % is not a known art), from among known polyester materials,aliphatic isophthalic diisocyanate of 7 to 11 wt % (molecular weight(MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfieldviscometer)) (where, wt % is not a known art), polyester sulfur oxidediol of 1 to 5 wt % as water based monomer (molecular weight (MW) is 400to 500 and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)),and water of 49 to 53 wt % are uniformly mixed; drying the coated sewingthread in a temperature range of 120 to 180° C. for 20 to 60 seconds;curing the dried sewing thread in a temperature range of 150 to 200° C.for 20 to 40 seconds; elongating the cured sewing thread in atemperature range of 150 to 200° C. for 15 to 20 seconds so that thesewing thread has elongation of 30 to 60%; and winding the elongatedsewing thread.

A main material for the coating liquid is polyester. In order toincrease an adhesive property, aliphatic isophthalic diisocyanate (thatis, a non-yellow characteristic cross-linking agent) of 7 to 11 wt % isadded.

In case where aliphatic isocyanate of less than 7 wt % is mixed, theadhesive strength of the coating liquid is low. In case where aliphaticisocyanate of more than 11 wt % is mixed, the viscosity of the coatingliquid is high and so workability is low. Accordingly, aliphaticisocyanate of 7 to 11 wt % preferably is mixed.

In order to make the coating liquid water-based, polyester sulfur oxidediol (that is, a water based monomer material) of 1 to 5 wt % having anMW of 400 to 500 and viscosity of 500 to 1000 CPS/25° C. (Brookfieldviscometer) (where, wt % is not a known art) is adeed. Further, water of49 to 53 wt % is added as a diluent for controlling viscosity.

The reason why water is added is that water serves as a diluent and thepadding process may not be properly performed because the main materialhas a high viscosity.

In case where water of less than 49 wt % is mixed, viscosity is high andso workability is difficult. In case where water of more than 53 wt % ismixed, there is a possiblity that the adhesive strength of the coatingliquid may be low. Accordingly, water of 49 to 53 wt % preferably isadded.

The catalyst of 1 to 5 wt % is added, preferably 2 wt %. The catalystfunctions to rapidly dry the coating liquid padded to the bond sewingthread and to control the strength of the bond sewing thread. The amountof the catalyst mixed can be various according to circumstances. In casewhere the catalyst of less than 1 wt % is mixed, the strength of thebond sewing thread is weak and the dry time is long. In case where thecatalyst of more than 5 wt % is mixed, the padding process for thecoating liquid is difficult because of the evaporation of moisture andthe efficiency of the sewing thread may be low because of high strength.Accordingly, the catalyst of 1 to 5 wt % preferably is mixed.

In accordance with a preferred embodiment of the present invention, thecatalyst is formed by mixing aliphatic isophthalic diisocyanate andethyl acetate in order to control strength. Catalyst components,composed of aliphatic isophthalic diisocyanate of 75%, ethyl acetate of15%, and other additives of 10%, can preferably be used.

The sewing thread is coated by dipping it in the coating liquid. Thisprocess is performed to make uniform the bonding of the sewing thread. Abonding pickup ratio may be in the range of 80 to 100% depending on thethickness of a raw thread.

In the padding process, the coating is performed by dipping the coatingliquid in a padding vessel and soaking the sewing thread. Here, thecoating liquid does not become hard at normal temperature because it isa water based material. Accordingly, the process can be rapidlyperformed because an additional heating process is not required.

The coated sewing thread is dried in a temperature range of 120 to 180°C. for 20 to 60 seconds. In a process of the coated sewing threadpassing through a heat chamber, the coated sewing thread is fully dried.

In case where the dry temperature is less than 120° C. or the dry timeis less than 20 seconds, the dry of the coated sewing thread is notproperly performed. In this case, there is a possibility that thecoating liquid may be peeled off. In case where the dry temperature ismore than 180° C. or the dry time is less than 60 seconds, the coatingliquid and the sewing thread may be thermally transformed and energy canbe lost. Accordingly, it is preferred that the coated sewing thread bedried in a temperature range of 120 to 180° C. for 20 to 60 seconds.

The dried sewing thread is thermally processed in a temperature range of150 to 200° C. for 20 to 40 seconds in order to increase elongation andharden the sewing thread. In particular, the curing process must beperformed when the sewing thread is processed by using water repellents.In this case, the sewing thread is thermally processed in a sealed heatchamber in a temperature range of 150 to 200° C. for 20 to 40 seconds sothat the dried coating liquid and the sewing thread can be integrallysticked.

In case where the processing temperature is less than 150° C. or theprocessing time is less than 20 seconds, the thermal processing purposefor increasing elongation and hardening the sewing thread cannot beachieved. In case where the processing temperature is more than 200° C.or the processing time is more than 40 seconds, the coating liquid andthe sewing thread may be thermally transformed, and energy can be lost.Accordingly, it is preferred that the thermal processing be performed ina temperature range of 150 to 200° C. for 20 to 40 seconds.

The cured sewing thread is elongated in a temperature range of 150 to200° C. for 15 to 20 seconds so that the sewing thread has elongation of30 to 60%. The elongated sewing thread is subjected to the windingprocess, packed, and finally completed as a product.

The elongation process can be performed by using a common method. Inthis method, in order to achieve elongation of 30 to 60%, the sewingthread is elongated and processed in a temperature range of 150 to 200°C. for 15 to 20 seconds which are similar to those of the curing processperformed in order to increase elongation.

For reference, the elongation process is a process of reducing thelinear density by lengthily extending a bundle of threads in a spinningprocess. Through the process, the orientation of polymer within a fiberis improved, and tensile strength and elasticity of the fiber areincreased.

In accordance with a preferred embodiment of the present invention, thecoating liquid can further comprise water repellent liquid in whichwater repellents of 3 to 8 wt % are mixed with water based bond of 46 to51 wt % and water of 46 to 51 wt %.

If the water repellent liquid is added to the coating liquid, the waterrepellent liquid penetrates the sewing thread, thus preventing moistureor a change of the dimensions.

Accordingly, an anti-working ability (that is, an ability to resist thepenetration of water or moisture) can be increased.

The water based bond of 46 to 51 wt % is mixed. Adhesive strength mustbe given to the water based bond so that the water repellents firmlystick to the sewing thread. Water is used to control viscosity and thussolve the difficulty of a task. It is preferred that a ratio of thewater based bond versus water be 1:1. Fluorinated water repellents areused as the water repellents. It is preferred that the water repellentsof 3 to 8 wt % be mixed so that the water repellents are uniformly mixedwith the coating liquid and a desired water repellent function can beproperly performed.

In accordance with water based bond sewing thread and the method ofmanufacturing the same according to the present invention, there areadvantages in that flexibility is excellent, durability and strength arehigh and freely controlled, a risk of fading and a change of color isremarkably decreased and color reproducibility and a feeling of use areexcellent even for a long time use, the manufacturing cost is low, and asupplied price is economical.

Furthermore, there are advantages in that working environments can beimproved and a risk of a fire is low because a water based coatingmethod not generating any toxic gases is used, additional process is notused in case where waterproof thread is manufactured by using waterbased bond sewing thread, and water treatment can be easily performedbecause some waterproof liquid can be mixed in a process of coating thesewing thread.

Further, in the above description, the above three products; polyesterpolyol, aliphatic isophthalic diisocyanate having a molecular weight(MW) of 222.2 and viscosity of 500 to 1000 CPS/25° C. (Brookfieldviscometer), and polyester sulfur oxide diol (that is, a water basedmonomer material) having an MW of 400 to 500 and viscosity of 500 to1000 CPS/25° C. (Brookfield viscometer) (produced by Hanyoung IndustryCo., Ltd., Korea) are known in the art and widely used.

While the present invention has been described with reference to theparticular illustrative embodiments, it is not to be restricted by theembodiments but only by the appended claims. It is to be appreciatedthat those skilled in the art can change or modify the embodimentswithout departing from the scope and spirit of the present invention.

1. A method of manufacturing a bonded sewing thread, comprising thesteps of: forming a mixed coating liquid by adding catalyst of 1 to 5 wt% to a mixture of 95 to 99 wt % in which polyester polyol of 39 to 43 wt%, aliphatic isophthalic diisocyanate of 7 to 11 wt % (molecular weight(MW) is 222.2 and viscosity is 500 to 1000 CPS/25° C. (Brookfieldviscometer)), polyester sulfur oxide diol of 1 to 5 wt % as water basedmonomer (molecular weight (MW) is 400 to 500 and viscosity is 500 to1000 CPS/25° C. (Brookfield viscometer)), and water of 49 to 53 wt % areuniformly mixed; coating the sewing thread by dipping the sewing threadin the mixed coating liquid; drying the coated sewing thread in atemperature range of 120 to 180° C. for 20 to 60 seconds; curing thedried sewing thread in a temperature range of 150 to 200° C. for 20 to40 seconds; elongating the cured sewing thread in a temperature range of150 to 200° C. for 15 to 20 seconds so that the sewing thread haselongation of 30 to 60%; and winding the elongated sewing thread.
 2. Themethod according to claim 1, wherein the catalyst is formed by mixingaliphatic isophthalic diisocyanate and ethyl acetate and used to controlstrength.
 3. The method according to claim 1, wherein the coating liquidfurther comprises water repellent liquid in which water based bond of 46to 51 wt %, water of 46 to 51 wt %, and water repellents of 3 to 8 wt %are mixed.
 4. A bonded sewing thread manufactured by coating the sewingthread by dipping the sewing thread in coating liquid, produced bymixing catalyst of 1 to 5 wt % and a mixture of 95 to 99 wt % in whichpolyester polyol of 39 to 43 wt %, aliphatic isophthalic diisocyanate of7 to 11 wt % (molecular weight (MW) is 222.2 and viscosity is 500 to1000 CPS/25° C. (Brookfield viscometer)), polyester sulfur oxide diol of1 to 5 wt % as water based monomer (molecular weight (MW) is 400 to 500and viscosity is 500 to 1000 CPS/25° C. (Brookfield viscometer)), andwater of 49 to 53 wt % are uniformly mixed; drying the coated sewingthread in a temperature range of 120 to 180° C. for 20 to 60 seconds;curing the dried sewing thread in a temperature range of 150 to 200° C.for 20 to 40 seconds; elongating the cured sewing thread in atemperature range of 150 to 200° C. for 15 to 20 seconds so that thesewing thread has elongation of 30 to 60%; and winding the elongatedsewing thread.
 5. The bond sewing thread according to claim 4, whereinthe catalyst is formed by mixing aliphatic isophthalic diisocyanate andethyl acetate and used to control strength.
 6. The bond sewing threadaccording to claim 4, wherein the coating liquid further comprises waterrepellent liquid in which water based bond of 46 to 51 wt %, water of 46to 51 wt %, and water repellents of 3 to 8 wt % are mixed.
 7. The methodaccording to claim 2, wherein the coating liquid further comprises waterrepellent liquid in which water based bond of 46 to 51 wt %, water of 46to 51 wt %, and water repellents of 3 to 8 wt % are mixed.
 8. The bondsewing thread according to claim 5, wherein the coating liquid furthercomprises water repellent liquid in which water based bond of 46 to 51wt %, water of 46 to 51 wt %, and water repellents of 3 to 8 wt % aremixed.